What are all these different races?

Can someone please explain the to me all the different types of track racing? I know what pursuits are, but everything else is confusing (and is a sprint a short TT-type thing or a head-to-head with lots of trackstanding and a proper sprint finish?). Things like Keirin, Madison, Derny, points races and all that lot.

Track racing is aggressive and crashes are common, but rarely serious. One of the worst in recent Australian racing was Craig Milton's now legendary spill in Launceston in 1985. Milton went down when a tyre blew out on him, and as he landed his pedal dug up a splinter of the then-new track surface. A 33cm long, 1cm wide spike entered his torso just under the armpit, puncturing his lung and stopping 1cm from his heart. The spike had to be broken off the track surface so Milton could be removed and he spent 8 hours under the knife as surgeons pulled bits of wood out of the wound. Milton got back on the bike a week later to win the Australian 10 mile and team pursuit championships. His effort in the team pursuit tore open the stitches and he finished the event with his blue NSW track squad strip dyed red, and had to immediately return to hospital. The spike is on display in his bike shop in Cronulla.